Booth Mul N Bit.docx

BOOTH_ MULTIPLIER FOR 16_BIT: module multiplier(prod, busy, mc, mp, clk, start); output [15:0] prod; output busy; input [7:0] mc, mp; input clk, start; reg [7:0] A, Q, M; reg Q_1; reg [3:0] count; wire [7:0] sum, difference; always @(posedge clk) begin if (start) begin A <= 8'b0; M <= mc; Q <= mp; Q_1 <= 1'b0; count <= 4'b0; end else begin case ({Q[0], Q_1}) 2'b0_1 : {A, Q, Q_1} <= {sum[7], sum, Q}; 2'b1_0 : {A, Q, Q_1} <= {difference[7], difference, Q}; default: {A, Q, Q_1} <= {A[7], A, Q}; endcase count <= count + 1'b1; end end alu adder (sum, A, M, 1'b0);

alu subtracter (difference, A, ~M, 1'b1); assign prod = {A, Q}; assign busy = (count < 8); endmodule //The following is an alu. //It is an adder, but capable of subtraction: //Recall that subtraction means adding the two's complement-//a - b = a + (-b) = a + (inverted b + 1) //The 1 will be coming in as cin (carry-in) module alu(out, a, b, cin); output [7:0] out; input [7:0] a; input [7:0] b; input cin; assign out = a + b + cin; endmodule MULTIPLIER_TB FOR 16 BIT : module multiplier_tb; reg clk, start; reg [7:0] a, b; wire [15:0] ab; wire busy; multiplier multiplier1(ab, busy, a, b, clk, start); initial begin clk = 0; $display("first example: a = 3 b = 17"); a = 3; b = 17; start = 1; #50 start = 0; #80 $display("first example done"); $display("second example: a = 7 b = 7");

a = 7; b = 7; start = 1; #50 start = 0; #80 $display("second example done"); $finish; end always #5 clk = !clk; always @(posedge clk) $strobe("ab: %d busy: %d at time=%t", ab, busy, $stime); endmodule GRAPH:

N_BIT MULTIPLIER : module multiplier_n(X, Y, Z); parameter n=32; input [n-1:0] X, Y; output [2*n-1:0] Z; reg [2*n-1:0] Z; reg [1:0] temp; integer i; reg E1,t; reg [n-1:0] Y1; always @(X,Y) begin Z = 0;

E1 = 1'd0; Y1 = - Y; Z[n-1:0]=X; for (i = 0; i < n; i = i + 1) begin temp = {X[i], E1}; case (temp) 2'd2 : Z [2*n-1 : n] = Z [2*n-1 : n] + Y1; 2'd1 : Z [2*n-1 : n] = Z [2*n-1 : n] + Y; default : begin end endcase t=Z[0]; Z = Z >> 1; Z[2*n-1] = t; E1 = t; end end endmodule TEST BEANCH FO N_BIT MULTIPLIER: module multipliern_tb(); reg [31:0] X, Y; wire [63:0] Z; multiplier_n mn(X, Y, Z); initial begin Y=4565;X=1106; #10 $finish end endmodule

GRAPH: